Pureflow Bio

PUREFLOW BIO / ENGINEERING FIELD GUIDE

Catfish FarmingSystems, Water Quality and Equipment

African catfish farming in RAS: water values, growth time, stocking density, why catfish cope with crowding, feeding, sorting, cannibalism and channel catfish.

11 MIN GUIDEUPDATED NOVEMBER 2026
Concept illustration of culture tanks connected to a complete RAS water-treatment train.SYSTEM CONCEPT
AI-generated educational concept illustration; not a Pureflow installation photograph or an approved construction drawing.
01Understand the mechanismInspect the relevant process stages.
02Review the operating dutyKeep assumptions and measured values visible.
03Prepare the next decisionUse the guide, tools and project checks.
INTERACTIVE PROCESS ATLAS

See the mechanism.
Understand the duty.

Select a route or a stage to inspect the process. The cutaway explains the equipment and water environment; it is a teaching illustration, not a project drawing.

Swipe horizontally to inspect the equipment. Stage buttons below also centre the selected component.
Inside a recirculating aquaculture treatment systemA cutaway culture tank connects to a rotary drum screen, moving bed biofilter, degassing tower, sump and pump, oxygen cone and enclosed UV reactor. Blue arrows follow recirculating water. An amber line takes drum-filter waste out of the loop. Equipment shapes and motion explain the process; dimensions and timing are illustrative.SEPARATE WASTE ROUTE VENTILATED OFF-GASCONTROLLED O₂ SUPPLY01 CULTURE TANK02 DRUM SCREEN03 MOVING BED04 DEGASSING05 SUMP + PUMP06 OXYGENATION07 UV TREATMENTTAN-NNH₄⁺ → NO₂⁻ → NO₃⁻PUREFLOW / INTERACTIVE PROCESS ATLASCONCEPT LAYOUT · NOT TO SCALE
Follow culture water through the coordinated treatment train and back to the stock.
Selected process stage

Culture tanks

Collect waste before it settles.

How it works

The culture tank is both an animal environment and a hydraulic vessel. The return flow should distribute oxygenated water and move settleable waste toward the intended outlet. Tank shape, drain arrangement and the behaviour of the stock determine how well this happens.

What to establish
  • Confirm the operating water volume and peak feed.
  • Check circulation, drain capture and access for inspection.
  • Record oxygen at the animal zone, not only in the return pipe.

Read about biomass and loading ↗

Filtration mode. Wash sequence and timing are illustrative. Geometry, stage order, pipe routes and equipment configuration are conceptual. Use the approved project design, operating instructions and verified model data.

Key takeaways

  • Best growth near 28 °C. At 16 °C they hardly eat.
  • They can survive low oxygen by breathing air, but the biofilter still needs oxygen in the water.
  • Densities of 100 to 350 kg/m³ are common in tanks.
  • Grade often and feed often to stop cannibalism.
Reference illustration for Catfish Farming: Systems, Water Quality and Equipment
Equipment reference visual; not evidence of a completed installation.
THE SHORT ANSWER

Ideal water values for african catfish

ParameterTargetNotes
Temperature26 to 28 °CBest around 28 °C
Dissolved oxygenAbove 3 to 4 mg/LFish breathe air but waste breakdown needs oxygen
pH6.8 to 7.5Nitrifiers slow below 6.8
Total ammoniaLowKeep as low as practical
Catfish Farming - Pureflow Bio
Reference visual. Equipment configuration and project details must be confirmed separately.
AQUACULTURE & RAS

How long does it take to grow?

About seven months from hatching to roughly 0.5 to 1.5 kg at the right temperature.

PLANNING WORKBENCH

Work with your own numbers.

Use the tools below to explore the relevant arithmetic. Enter measured values or declared assumptions. An estimate does not establish equipment capacity, biological performance or a safe operating limit.

Feed & loading scenario

Translate a selected feeding rate and assumed waste yield into a planning load.

Assumptions and limits

The feeding rate and TAN yield are supplied assumptions. Use the species, feed, growth stage and verified process design; the estimate is not a Pureflow capacity rating.

—Daily feed · kg/day
—Estimated TAN-N · kg/day
Enter your values, or load the labelled arithmetic example. No design values are pre-filled.
FormulaFeed = biomass × feeding rate ÷ 100. TAN-N = feed × assumed yield ÷ 1,000.
Convert units before you calculate
Choose units and enter a value.

Planning arithmetic · inputs remain visible for review · example values are not operating recommendations

AQUACULTURE & RAS

Stocking density: how many per cubic metre?

Why catfish cope with crowding

Air breathing lets them use surface air. Densities of 100 to 350 kg/m³ are common, and some farms go higher.

What it means for your system

High density means a very high solids and ammonia load. Use strong drum filtration and a generous biofilter. See stocking density.

Example: 10 m³ of catfish tanks

At 200 kg/m³ that is 2 tonnes of fish. Feed several percent of body weight daily, so daily feed can be tens of kilos.

AQUACULTURE & RAS

Feeding african catfish

Fish sizeAt 28 °CAt 20 °C
1 to 10 g10%5%
10 to 25 g7%3%
25 to 50 g5.5%2%
50 to 100 g4%1.5%
100 to 300 g3.5%1.2%
300 to 800 g3.1%1%

Percent of body weight a day.

AQUACULTURE & RAS

Sorting juveniles and stopping cannibalism

  1. Grade oftenSeparate by size regularly.
  2. Feed oftenHungry fish bite each other.
  3. Keep it dimLow light reduces aggression.
  4. Keep groups dense and evenUniform size groups settle.
Catfish Farming - Pureflow Bio
Reference visual. Equipment configuration and project details must be confirmed separately.
AQUACULTURE & RAS

Where fingerlings come from

Hatcheries use hormone-induced spawning and stripped eggs. Buy from reliable sources.

AQUACULTURE & RAS

Channel catfish: the pond catfish of the united states

African catfishChannel catfish
BreathingGills and airGills only: ponds need night aeration
Main systemIndoor RAS tanksEarthen ponds
Time to marketAbout 7 months18 to 36 months
PROJECT REVIEW

Review the design at peak load

Use these questions to prepare a project brief or an operating review. Check an item only when the information has been recorded for your installation.

0 of 3 checked

This checklist is a working aid in the current page session, not a saved maintenance record.

QUESTIONS

Catfish Farming FAQ

Why do catfish fight?

Size differences lead to cannibalism. Grade often.

What temperature do catfish need?

26 to 28 °C is ideal.

Do catfish need oxygen if they breathe air?

Yes. The biofilter and waste breakdown still need oxygen in the water.

KEEP READING

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